Scale Drawing/Transcript
Transcript Title text reads, The Mysteries of Life with Tim and Moby Moby is painting a giant Moby head on the wall. Tim enters the room. TIM: Hey, this was supposed to be finished an hour ago… and I thought you were painting both of us. Moby beeps. He shows Tim a photo of the two of them. TIM: Well, if your head's that big, where am I supposed to fit in? A letter appears. Text reads as Tim narrates: Dear Tim and Moby, how do I scale something I want to draw? From, Lucky1 TIM: Well, you start with the thing you want to scale. Moby’s supposedly making a mural of this picture, but I think he needs to put down the paintbrush and do a little math first. Our picture measures 10 centimeters by 15 centimeters. On-screen, a ruler measures the length and width of the photo. TIM: Now we measure the surface we're transferring the image to; in this case, the wall. Moby beeps. He uses a tape measure to measure the length and width of the wall. TIM: It’s 3 meters by 4.5 meters. To find the scale of Moby’s painting, we need to make a ratio: the actual height of the picture over the scaled height. That's 10 centimeters over 3 meters. A fraction appears, reading, 10 centimeters over 3 meters. Moby beeps. TIM: Sure, we can convert the meters to centimeters to make it simpler. 3 meters times 100 centimeters per meter is 300 centimeters. Onscreen, the fraction, 10 centimeters over 3 meters, becomes 10 centimeters over 300 centimeters. TIM: We can reduce this ratio to, 1 to 30. An equation appears, reading, 10 centimeters over 300 centimeters equals 1 centimeter over 30 centimeters. TIM: So our height scale in centimeters is, 1 to 30; 1 centimeter on the picture equals 30 centimeters on the wall. Let’s do the same for the width. The picture is 15 centimeters wide, and the wall is 4.5 meters wide. 4.5 meters is 450 centimeters. An equation appears, reading, 15 centimeters over 4.5 meters equals 15 centimeters over 450 centimeters. TIM: Our ratio reduces to, 1 centimeter over 30 centimeters. An equation appears, reading, 15 centimeters over 450 centimeters equals 1 centimeter over 30 centimeters. TIM: Great; our width scale is also 1 to 30. That's good, because when your height and width scales are different, you end up with a stretched picture. On-screen, the picture stretches lengthwise and widthwise. Moby beeps. TIM: Now we know that 1 square centimeter on the picture equals a square 30 centimeters by 30 centimeters on the wall. And here's the trick that makes scale drawing easy. We make a grid on the picture, dividing it up into 1-centimeter boxes. On-screen, a grid appears on the picture. TIM: Then we do the same on the wall, using the scale of our ratio. Moby draws lines on the wall with a pencil. TIM: Since our scale is 1 centimeter to 30 centimeters, our grid on the wall divides the wall up into 30-centimeter squares. On-screen, a grid covers the wall. TIM: That way, one block on the picture will be scaled to one block on the wall. Now all Moby has to do is paint what’s in the picture on the wall, square by square, and his mural will be to scale! Moby beeps. TIM: Well, sure, I’ll start you off. See, it’s just a matter of copying the information in this 1 by 1 centimeter square to the 30 by 30 centimeter square on the wall. On-screen, Tim pencils in one square on the wall to match the corresponding square in the picture. TIM: There. That looks pretty good. Now we just pencil in the rest of the squares in the grid, paint it, and we're… we're… done. On-screen, Tim looks around. Moby is gone. TIM: Moby? Tim turns to see a swing and a slide. TIM: Hrrrm. On-screen, Tim finishes penciling the mural by himself. Tim sighs. Category:BrainPOP Transcripts